(d) Ozone-depleting substances are man-made gases that destroy ozone once the gases reach the ozone layer. The ozone layer sits in the upper atmosphere and reduces the amount of harmful ultraviolet radiation that reaches the earth from the sun. Ultraviolet radiation can have detrimental effects on both humans and the environment. Ozone-depleting substances include– chlorofluorocarbons (CFCs),hydrochlorofluorocarbons (HCFCs),hydrobromofluorocarbons (HBFCs),halons, methyl bromide, carbon tetrachloride, methyl chloroform.